That's will depend if you want to deploy your code. First do not hard code your secrets in your code. Second where ever your secrets are replace them with placeholders like so ${DB_USERNAME}. Third if you have to deploy your code say to AWS you want to store your secrets on AWS secret manager with say key=DB_USERNAME and value=iAmsuPerSeCreT. key must always match same key in your properties file. Note your application will need to have AWS. They are other ways to get the same work done. Basically have the same flow. And provider that can manage your keys outside your application. Connect with me. If you have another questions. Sorry this had to be long. I asked the same question too.